Add --no-wait flag to sync command

[Copilot]

Closes #[issue-number]

Description

Adds --no-wait flag to the sync command to exit after creating blob resources without waiting for download completion. Enables fire-and-forget bulk syncing where large image layers download asynchronously.

Changes

• Command interface: Added --no-wait boolean flag to sync command
• Sync flow: Thread noWait parameter through SyncImage() → syncManifestAndBlobs() → syncManifestBlobs() → CIDN client
• CIDN client: Modified Blob() and ManifestDigest() to skip waitForBlob() when noWait=true
• Backward compatibility: Gateway/proxy paths always pass noWait=false to maintain existing behavior

Implementation Notes

Manifests always wait regardless of flag since they're small (<10KB) and required to parse image metadata. Only large layer blobs skip waiting.

# Waits for all blobs to complete (default)
sync --storage-url s3://bucket docker.io/library/nginx:latest

# Exits after creating blob resources
sync --no-wait --storage-url s3://bucket docker.io/library/nginx:latest

Original prompt

---

This section details on the original issue you should resolve

<issue_title>sync support no wait</issue_title>
<issue_description>Add a flag to sync to support exiting after all blobs are created, instead of waiting for them to complete.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes sync support no wait #53

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.